Land surface feedbacks and palaeomonsoons in northern Africa

A. Broström; M. Coe; S. P. Harrison; R. Gallimore; J. E. Kutzbach; J. Foley; I. C. Prentice; P. Behling

Land surface feedbacks and palaeomonsoons in northern Africa

A. Broström^*, M. Coe, S. P. Harrison, R. Gallimore, J. E. Kutzbach, J. Foley, I. C. Prentice, P. Behling

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

111 Citations (Scopus)

Abstract

We ran a sequence of climate model experiments for 6000 years ago, with land-surface conditions based on a realistic map of palaeovegetation, lakes and wetlands, to quantify the effects of land-surface feedbacks in the Saharan region. Vegetation-induced albedo and moisture flux changes produced year-round warming, forced the monsoon to 17°-25°N two months earlier, and shifted the precipitation belt ≃300 km northwards compared to the effects of orbital forcing alone. The addition of lakes and wetlands produced localized changes in evaporation and precipitation, but caused no further extension of the monsoon belt. Diagnositc analyses with biome and continent hydrology models showed that the combined land-surface feedbacks, although substantial, could neither maintain grassland as far north as observed (≃26°N) nor maintain Lake 'MegaChad' (330 000km²).

Original language	English
Pages (from-to)	3615-3618
Number of pages	4
Journal	Geophysical Research Letters
Volume	25
Issue number	19
Publication status	Published - 1 Oct 1998
Externally published	Yes

Cite this

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title = "Land surface feedbacks and palaeomonsoons in northern Africa",

abstract = "We ran a sequence of climate model experiments for 6000 years ago, with land-surface conditions based on a realistic map of palaeovegetation, lakes and wetlands, to quantify the effects of land-surface feedbacks in the Saharan region. Vegetation-induced albedo and moisture flux changes produced year-round warming, forced the monsoon to 17°-25°N two months earlier, and shifted the precipitation belt ≃300 km northwards compared to the effects of orbital forcing alone. The addition of lakes and wetlands produced localized changes in evaporation and precipitation, but caused no further extension of the monsoon belt. Diagnositc analyses with biome and continent hydrology models showed that the combined land-surface feedbacks, although substantial, could neither maintain grassland as far north as observed (≃26°N) nor maintain Lake 'MegaChad' (330 000km2).",

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T1 - Land surface feedbacks and palaeomonsoons in northern Africa

AU - Broström, A.

AU - Coe, M.

AU - Harrison, S. P.

AU - Gallimore, R.

AU - Kutzbach, J. E.

AU - Foley, J.

AU - Prentice, I. C.

AU - Behling, P.

PY - 1998/10/1

Y1 - 1998/10/1

N2 - We ran a sequence of climate model experiments for 6000 years ago, with land-surface conditions based on a realistic map of palaeovegetation, lakes and wetlands, to quantify the effects of land-surface feedbacks in the Saharan region. Vegetation-induced albedo and moisture flux changes produced year-round warming, forced the monsoon to 17°-25°N two months earlier, and shifted the precipitation belt ≃300 km northwards compared to the effects of orbital forcing alone. The addition of lakes and wetlands produced localized changes in evaporation and precipitation, but caused no further extension of the monsoon belt. Diagnositc analyses with biome and continent hydrology models showed that the combined land-surface feedbacks, although substantial, could neither maintain grassland as far north as observed (≃26°N) nor maintain Lake 'MegaChad' (330 000km2).

AB - We ran a sequence of climate model experiments for 6000 years ago, with land-surface conditions based on a realistic map of palaeovegetation, lakes and wetlands, to quantify the effects of land-surface feedbacks in the Saharan region. Vegetation-induced albedo and moisture flux changes produced year-round warming, forced the monsoon to 17°-25°N two months earlier, and shifted the precipitation belt ≃300 km northwards compared to the effects of orbital forcing alone. The addition of lakes and wetlands produced localized changes in evaporation and precipitation, but caused no further extension of the monsoon belt. Diagnositc analyses with biome and continent hydrology models showed that the combined land-surface feedbacks, although substantial, could neither maintain grassland as far north as observed (≃26°N) nor maintain Lake 'MegaChad' (330 000km2).

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Land surface feedbacks and palaeomonsoons in northern Africa

Abstract

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